Micromirror arrays are key components of microelectromechanical system (MEMS)-based spatial light modulators (SLMs). SLMs are transducers that modulate an incident beam of light in a spatial pattern that corresponds to an optical or electrical input. A typical MEMS-based SLM consists of an array of individually addressable micromirrors. Each micromirror consists of a deflectable reflective mirror plate that is attached to a deformable hinge formed on a substrate such that the mirror plate can rotate on the substrate. Each individual mirror plate can be deflected independently by an electrostatic force. The electrostatic force is derived from an electrostatic field established between the mirror plate and an electrode. Reflection of a beam of incident light incident on a micromirror can then be controlled, for example, by deflecting the micromirror through changing the electrostatic force applied to the micromirror. MEMS-based SLM have experienced significant developments and have been implemented in many applications, one of which is the use in digital display systems. In a display application, each micromirror is associated with a pixel of a displayed image. To produce a bright pixel, the state of the micromirror associated with the pixel is set in such a way that the reflected light from the micromirror is directed onto a target for viewing. To produce a dark pixel, the state of the micromirror is tuned such that the reflected light from the micromirror is directed away from the display device. In order to display a black-and-white image, the micromirror array is illuminated by a beam of light. By coordinating the reflective status of the micromirrors based on the brightness of the pixels of the desired image, the collective effect of all reflected lights from individual micromirrors is the generation of the desired image. Gray-scaled and colored images can also be displayed using the micromirror array with the pulse-width-modulation and sequential-color display techniques, which will not be discussed in detail herein.
Variations of the micromirror array, of which the SLM is comprised, have been developed. Regardless of the variations, the micromirror is the key component of an SLM used for display systems and the quality of a displayed image depends on the integrity and function of that micromirror. Therefore, a method and device that will simplify the product and the fabrication thereof is needed.